Sift the flour 3 times. Beat the yolks of the eggs until light, add the
sugar which has been sifted several times and beat with eggs until mixture
is creamy. Beat the whites of eggs until stiff adding the cream of tartar
when partly beaten. Combine the egg mixtures and fold in gently the sifted
flour, then the vanilla. Do not beat. Pour into a well-buttered loaf pan
which has been sprinkled lightly with flour. Bake at 350+F for 20 minutes.
Increase heat to 400+F and bake about 40 minutes. Source: Pennsylvania
Dutch Cook Book - Fine Old Recipes, Culinary Arts Press, 1936.